Hanger apparatus for well pipe



Nov. 19, 1968 J. W. E HANES HANGER APPARATUS FOR WELL PIPE 2 Sheets-Sheet 1 Filed Dec. 28, 1966 I'm/sum.

CEMES WE Hauss i I TTORNEY.

Nov. 19, 1968 J. w. E. HANES HANGER APPARATUS FOR WELL PIPE} 2 Sheets-Shet 2 Filed Dec. 28, 1966 [Wen/roe. a: (#74455 WE Hnmss United States Patent 3,411,588 HANGER APPARATUS FOR WELL PIPE James W. E. Hanes, Ventura, Calif., assignor to Ventura Tool Company, Ventura, Calif., a corporation of California Filed Dec. 28, 1966, Ser. No. 605,468 22 Claims. (Cl. 166-208) The present invention [relates to casing systems for underwater or subsea well bores, and more particularly to apparatus for hanging casing or tubing in a casing system.

In the drilling of underwater wells, a drilling platform is used. Instead of supporting the several concentric strings of easing from the floor of the platform, it is desirable to effect their support or hanging at or near the mudline where the casing strings are interconnected by the casing head system. Risers extend from the casing head system to the platform, there being blowout preventer equipment attached to the casing head system. Upon completion and successful testing of the well, the riser section of each string of easing (including the blowout preventer equipment) is backed off where it is supported, or at the mudline, and the well is capped.

Following capping of the well, the relatively heavy and large capacity drilling platform is removed from the well location, and a light production platform installed in its place. The last casing string, or perhaps the last two casing strings, that had been run in the well are extended to the production platform by securing risers to them. An outer casing is stripped over the smaller riser or risers, and cement poured in the annulus between the riser and outer casing to form a column. Since the weight of the several casing strings disposed in the well are carried at the mudline, the production platform need only be of sufficient capacity to support the load of the risers extending from the mudline to the platform, plus the weight of tubing hung from a casing head at the top of the aforementioned column and other production equipment required to produce the well.

Heretofore, a casing has been hung at or near the mudline by ues of slips. Where the casing load is great, serious design problems are encountered in developing a slip type hanger of sufficient strength to carry the load. In addition, the inside diameter of the string of casing previously installed in the well becomes restricted, reducing the size of drilling bit that can be run through the casing string already in the well bore, for the purpose of continuing the drilling of the well bore to the desired depth.

An object of the present invention is to provide casing hangefi'apparatus that does not impose restrictions on the inside diameter of a previously installed casing string, so that a drilling bit of large or maximum size can be run through it to drill an optimum size well bore, and thereby permit a larger size casing to be run subsequently in such well bore.

Another object of the invention is to provide casing hanger apparatus embodying a hanger of unrestricted inside diameter into which a hanger seat of an appropriate size can be set after the well bore has been drilled. An inner casing string may then be run in the well and supported from the hangerseat.

A further object of the invention is to provide a hanger seat and running tool apparatus for lowering the seat within a casing string or riser to a casing hanger head, and for setting the seat in the casing hanger head.

An additional object of the invention is to provide a simple, strong and sturdy casing hanger head and hanger seat to be set therein, in which the bore through the casing hanger head is initially unrestricted, the seat being subsequently installed in the hanger head to provide a support for an inner casing string.

Patented Nov. 19, 1968 Yet another object of the invention is to provide an expansible hanger seat and running tool combination, in which the hanger seat is initially in retracted position and is easily released from the running tool for expansion and movement into coupling relation to a casing hanger head.

Still a further object of the invention is to provide an expansible hanger seat and running tool combination, in which the seat is initially releasably secured to the running tool in retracted position, and in which release of the seat from the running tool is effected hydraulically, enabling the running tool to move the seat into position for expansion into its associated casing hanger head.

Another object of the invention is to provide an expansible hanger seat and running tool therefor, in which the running tool initially maintains the seat in retracted condition, release of the seat from the running tool being effected hydraulically to allow expansion of the seat into an associated casing hanger head, the running tool embodying a cleaning tool for insuring a clean condition of the casing hanger head for appropriate reception of the hanger seat.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a diagrammatic view, parts being disclosed in section, of an underwater or subsea well, with associated equipment used in drilling the well from a drilling platform;

FIG. 2 is an enlarged longitudinal section, with a portion thereof disclosed in side elevation, of a running tool and hanger seat being lowered to a casing hanger head in which the seat is to be installed;

FIG. 3 is a view similar to FIG. 2 disclosing the hanger seat released from the running tool;

FIG. 4 is a view similar to FIG. 3 disclosing the hanger seat installed in the casing hanger head, and the running tool in condition to be removed to the drilling platform.

As disclosed in the drawings, a well bore A has been drilled below a body of water B from a drilling platform C, which is suitably supported on a plurality of leg structures D driven into the ocean or subsea floor E. As disclosed, a plurality of concentric casing strings F, G, H have been installed in the well bore A and are supported from a suitable structure or base I resting on the subsea floor E, or at the mudline. Three concentric casing strings are disclosed in the drawings, but their number can be varied, if desired. The outermost casing string F is suitably carried at or near the mudline, the intermediate casing string G being secured to a hanger 10 resting upon an appropriate hanger seat 11 connected to the outermost casing string F. The inner casing string H is connected to a casing hanger head 12 resting upon an appropriate seat 13 of the intermediate hanger 10. It is desired to run yet another smaller diameter string of easing (not shown) through the inner casing string H and to be carried from the casing hanger head 12, after the well bore has been drilled to the required depth.

As specifically disclosed in the drawings, the casing hanger 12 includes a main body section 14 having a counterbore 15, the base 16 of the counterbore providing a support or upwardly facing shoulder against which a hanger seat 17 is to bear, as described hereinbelow. The casing hanger head further includes a coupling section 18,

including a pin 19 threadedly secured to a companion upper box 20 on the main body section, the threads 21 preferably being left-hand threads. The coupling section 18, in turn, is threadedly attached to a marine conductor pipe or riser K that extends upwardly through the body of water B to the drilling platform C. Although not disclosed in the drawings, a blowout preventer or a series of blowout preventers are disposed between the casing hanger body 12 and the riser K. Such blowout preventer or preventers are not shown since they form no part of the present invention.

The lower end 22 of the coupling section 18 is longitudinally spaced from the upwardly facing shoulder 16 of the main body section, such lower end and shoulder forming upper and lower sides of a circumferential groove 23 provided in the head 12, and into which the hanger seat 17 is adapted to expand for installation therein. This hanger seat is installed after the well has been drilled to the required depth, and in its absence, a suitable drill bit (not shown) may be connected to the lower end of a series of drill collars M, the upper end of which is connected to drill pipe N terminating in an upper kelly P supported from the usual swivel R carried by the travelling hook and block S, crown block T, and intervening cable W, mounted on the usual derrick Y forming part of the drill ing rig on the drilling platform C. The drill bit can be of a maximum size for passing downwardly through the marine conductor pipe or riser K, casing hanger head 12 and the casing H suspended therefrom, so as to be capable of drilling a maximum size of well bore below the inner casing string H.

After the well bore has been drilled by the drilling bit, or a plurality of drilling bits, the drilling string and the last bit are elevated from the well bore, and through the casing H and riser K to the drilling platform C. Thereafter, a hanger seat 17 of required size to expand outwardly into the casing hanger groove 23 is detachably secured to a running tool secured to the lower end of the drill collars M. This combination is run from the drilling platform through the riser toward the casing hanger head 12 by means of the drill pipe N connected to the drill collars M.

As specifically disclosed in the drawings, the hanger seat 17 comprises a sleeve or ring having a longitudinal split 31 extending completely therethrough, the hanger seat tending inherently to expand to a diameter that will bring it into snug engagement with the base 23a of the groove 23. In making the hanger seat, a solid sleeve having an outside diameter slightly greater than the diameter of the base 23a of the groove may be provided, and this sleeve or ring is cut longitudinally throughout its length to provide the split or gap 31. It is then contracted to a diameter slightly less than the inside diameter of the marine conductor pipe or riser K. This sleeve or ring 17 has a length which is greater than the length of the coupling spaces usually present between adjacent sections of the riser K. It will only fit within a groove or gap having a length slightly exceeding its length, which is the casing hanger groove 23. The groove 23 has a length substantially greater than the length of any groove or gap in the riser K and other equipment thereabove.

The casing hanger sleeve 17 has an inwardly projecting seating portion 35 constituted by an inwardly directed flange having an upper downwardly tapering seat 36 and a lower downwardly flaring surface 37a opening through the lower end of the seat. The seat 17 also has an upper reduced diameter portion 37 adapted to fit within a restraining skirt 38 of a body adapter 39 forming part of the running tool 30. When the reduced diameter upper portion 37 of the seat is disposed in the adapter39, an upwardly facing shoulder 40 on the hanger seat engages the lower end 41 of the adapter, the retracted outside diameter 42 of the hanger seat 17 then preferably being no greater than the outside diameter of the body adapter 39 of the running tool. The hanger seat 17 is releasably 4 secured to the body adapter 39 by a plurality of shear screws 43.

The running tool 30 further includes a main body 44 having an upper threaded pin 45 threadedly secured to the lower section of the string of drill collars M, or a drill collar adapter connected to the lowermost section of the drill collar and forming the lower portion of the drilling string that extends upwardly to the drilling platform C. The body adapter 39 is secured to the lower portion of the body 44 by a plurality of longitudinally extending cap screws 46 projecting through the upper portion of the body adaper, the heads 47 of the screws being received within a recess 48 in such upper portion. Initially disposed above the hanger seat 17 and in close proximity thereto, and initially engaging the body 44 and the body adapter 39, is a seat ejector plate or release member 49 which surrounds a hollow piston rod or conductor tube 50 secured to or integral with an actuator or actuating piston 51 slidably mounted within the body 44 of the running tool. The seat ejector plate 49 is secured to the piston 51 by a plurality of longitudinally extending cap screws 52.

Initially, the piston 51 and plate 49 are held in an upper position within the body 44 and adapter 39 of the running tool 30 by a helical compression spring 53 surrounding a lower portion of the piston, its lower end bearing against an inwardly directed body flange 54, its upper end engaging the lower end of a hollow piston head portion 55 of the actuating piston, which is slidable Within a cylinder 56 provided by the running tool body 44. Leakage of fluid between the cylinder wall and the piston head is prevented by a suitable seal ring 57, such as a rubber or rubber-like O ring, mounted in a peripheral piston groove 58 and slidably and sealingly engaging the wall of the cylinder.

As disclosed in the drawings, the conductor tube or pipe 50 is secured to the main body portion 60 of a cleaning tool 61, which is specifically illustrated as being a hydraulic cleaning tool, in which fluid will flow through the conductor tube or pipe 50 and laterally through passages 62 in the body of the cleaning tool, discharging through nozzles 63 that will eject high velocity streams of fluid against the wall of the riser pipe K and against portions of the casing hanger body 12 to clean the parts, and thereby offer assurance that the running tool 30 and casing hanger seat 17 can be lowered to the groove 23 in the casing hanger body 12, and can expand outwardly thereinto to its final seating position. Although a hydraulic or jet type of cleaning tool 61 is disclosed for purpose of illustration, a drill bit (not shown) can be used in its place, rotation of the drill bit effecting a cleaning action, as well as the fluid jets emanating from the usual drill bit nozzles. The fluid discharged from the nozzles 63 passes upwardly around the cleaning tool 61, flowing around the exterior of the retracted hanger seat 17, or into its interior, and through passages 65 in the seat ejector plate 49 that communicate with openings 66 in the body adapter, which, in turn, communicate with grooves 67 extending from the openings 66 into aligned circulation grooves 68 formed in the exterior of the body 44 of the running tool, the circulating fluid continuing upwardly around the drill collars M and drill pipe N back to the drilling platform C.

In connection with the installation of the hanger seat 17 in the casing hanger head 12, the hanger seat is contracted and is mounted within the restraining skirt 38 of the body adapter 39. The shear screws 43 are then applied to releasably secure the seat to the adapter, the running tool 30 and hanger seat 17 then being in the relative condition illustrated in FIG. 2, in which the hanger seat has clearance with the inner wall of the riser K. This combination of apparatus is lowered from the drilling platform C by means of the drill string N, M through the riser toward the casing hanger head 12. Circulating fluid may be pumped down through the drill string while it is being rotated to rotate the running tool 30, hanger seat 17 and the cleaning tool 61, the fluid jetting against the wall of the riser. As the apparatus is lowered through the riser, the cleaning tool 61 will also move downwardly past the casing hanger head 12, the fluid jetting into the groove 23 and insuring that such groove is or becomes clean. The lowering action is stopped before the hanger seat 17 is located in the casing hanger head 12, and preferably when it is positioned above the coupling section 18 of the casing hanger head.

After the cleaning action has been completed, a tripping member 70, such as a valve ball member, is dropped into the drilling string, gravitating or being pumped downwa-rdly therethrough until it engages a valve seat 71 within the hollow piston 51 formed on a seat insert 72 secured within the piston 51. Pressure can now be built up in the fluid within the string of drill pipe M, N, exerting a downward force on the piston 51 and on the seat ejector plate or release member 49, the latter bearing against the upper end of the hanger seat 17. When the pressure has increased sufliciently to overcome the shear strength of the screws 43, the latter are disrupted and the piston 51 and plate 49 moved downwardly to shift or eject the hanger seat 17 from the restraining skirt 38 of the body adapter 39, the hanger seat then expanding inherently outwardly into frictional engagement with the wall of the riser K.

The extent of expansion may be such that the plate 49 will still be engaged with the upper end of the hanger seat 17, as disclosed in FIG. 3. The running string M, N can now be lowered to cause corresponding lowering of the running tool 30, the plate forcing the hanger seat 17 downwardly within the riser so long as pump pressure is being applied to the fluid in the string of drill pipe. How ever, such pump pressure can be discontinued, allowing the spring 53 to elevate the piston 51 and plate 49 and move the plate back within the restraining skirt 38 of the body adapter. The lowering of the drill string M, N and running tool will cause the plate 49 to still engage the upper end of the hanger seat 17, or, if the latter has expanded outwardly beyond the diameter of the hanger plate, the lower end 41 of the restraining skirt 38 will then engage the upper end of the hanger seat to push the latter downwardly in the marine conductor pipe or riser. Downward sliding of the hanger seat in this manner continues until it slides along the wall of the coupling section 18 and becomes disposed opposite the circumferential groove 23 in the casing hanger, at which location it will snap outwardly inherently into the groove and come to rest with its lower end engaging the lower side 16 of the groove, as disclosed in FIG. 4. The string of drill pipe and collars M, N and running tool 30 can now be elevated through the riser K and removed entirely therefrom.

An inner string of easing or pipe (not shown) can now be lowered from the drilling platform C through the riser K, and an upper head (not shown) on such string ofpipe will come to rest upon the upper seat 36 of the casing hanger. Such head will preferably also be connected through a left-hand thread to a riser that extends through the riser K to the drilling platform.

As stated above, following the suspension of the casing or pipe from the casing hanger 17, and upon completion of the well in a required manner and its successful testing, the riser of each string of casing, such as the riser K, is backed off by rotating each riser to the right,.the disconnection being effective at their left-hand threads (as at the threads 21), and the well is capped. Thereafter, the drilling platform C is removed and a light production platform installed in its place, the well then being completed in the manner described above or other desired manner.

I claim:

1. In apparatus for suspending pipe in a well bore: a head having a circumferential recess therein; an inherently expandable hanger seat adapted to expand into said recess to provide a seat for supporting a string of pipe in the well bore; a running tool connectible to a tubular running-in string for lowering toward said head; means releasably connecting said hanger seat in retracted condition to said running tool; and means for releasing said hanger seat from said running tool to enable said hanger seat to expand inherently into said recess upon being lowered into transverse alignment therewith.

2. In apparatus as defined in claim 1; wherein said means for releasing said hanger seat comprises hydrau: lically actuatable means responsive to the pressure of fluid in the tubular running-in string.

3. In apparatus as defined in claim 1; wherein said means releasably connecting said hanger seat in retracted condition to said running tool comprises means on said running tool encompassing said hanger seat; said means for releasing said hanger seat ejecting said hanger seat from encompassing relation by said means on said running tool to permit said hanger seat to expand.

4. In apparatus as defined in claim 1; and a cleaning tool connected to and depending from said running tool for conditioning said recess for the reception of said hanger seat therein.

5. In apparatus as defined in claim 1; wherein said means releasably connecting said hanger seat in retracted condition to said running tool comprises means on said running tool encompassing said hanger seat; said means for releasing said hanger seat comprising hydraulically actuatable means responsive to the pressure of fluid in the tubular running-in string for ejecting said hanger seat from encompassing relation by said means on said running tool to permit said hanger seat to expand.

6. In apparatus as defined in claim 1; wherein said means releasably connecting said hanger seat in retracted condition to said running tool comprises means on said running tool encompassing said hanger seat; said means for releasing said hanger seat comprising hydraulically actuatable means responsive to the pressure of fluid in the tubular running-in string for ejecting said hanger seat from encompassing relation by said means on said running tool to permit said hanger seat to expand; and a cleaning tool connected to and depending from said running tool and adapted to discharge fluid pumped down the running-in string to condition said recess for the reception of said hanger seat therein.

7. In apparatus for suspending pipe in a Well bore: a head having a circumferential recess therein; a split, inherently expandable hanger seat adapted to expand into said recess to provide a seat for supporting a string of pipe in the well bore; a running tool comprising body means connectible to a tubular running-in string for lowering toward said head; means releasably connecting said hanger seat in retracted condition to said body means; and means engageable with said hanger seat and shiftable relative to said body means for releasing said hanger seat from said body means to enable said hanger seat to expand inherently into said recess upon being lowered into transverse alignment therewith.

8. In apparatus as defined in claim 7; wherein said means for releasing said hanger seat comprises hydraulically actuatable means responsive to the pressure of fluid in the tubular running-in string for shifting said hanger seat downwardly of said body means to released condition.

9. In apparatus as defined in claim 7; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; said means for releasing said hanger seat ejecting said hanger seat from encompassing relation by said skirt to permit said hanger seat to expand.

10. In apparatus as defined in claim 7; wherein said 'means releasably connecting said :hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; said means for releasing said hanger seat comprising hydraulically actuatable means responsive to the pressure of fluid in the tubular running-in strin for ejecting said hanger seat from encompassing relation by said skirt to permit said hanger seat to expand.

11. In apparatus as defined in claim 7; cylinder means in said body means; said releasing means comprising piston means in said cylinder means responsive to the pressure of fluid in the tubular running-in string for shifting said hanger seat downwardly of said body means to released condition.

12. In apparatus as defined in claim 7; cylinder means in said body means; said releasable means comprising tubular piston means in said cylinder means; and means adapted to be lowered through the tubular running-in string into engagement with said piston means torestrict the flow of fluid therethrough and allow fluid pressure to be built up in the tubular running-in string and cylinder means to shift said piston means downwardly in said cylinder means to shift said hanger seat downwardly of said body means to released condition.

13. In apparatus as defined in claim 7; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; cylinder means in said body means; said releasing means comprising piston means in said cylinder means responsive to the pressure of fluid in the tubular running-in string for ejecting said hanger seat downwardly from encompassing relation by said skirt to permit said hanger seat to expand.

14. In apparatus as defined in claim 7; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; cylinder means in said body means; said releasing means comprising tubular piston means in said cylinder means; and means adapted to be lowered through the tubular running-in string into engagement with said piston means to restrict the flow of fluid therethrough and allow fluid pressure to be built up in the tubular running-in string and cylinder means to shift said piston means downwardly in said cylinder means and eject sa id hanger seat downwardly from encompassing relation by said skirt to permit said hanger seat to expand.

15. In apparatus as defined in claim 7; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; cylinder means in said body means; said releasing means comprising tubular piston means in said cylinder means; means adapted to be lowered through the tubular running-in string into engagement with said piston means to restrict the flow of fluid therethrough and allow fluid pressure to be built up in the tubular running-in string and cylinder means to shift said piston means downwardly in said cylinder means and eject said hanger seat downwardly from encompassing relation by said skirt to permit said hanger seat to expand; and a cleaning tool connected to and depending from said tubular piston means and adapted to discharge fluid pumped down the running-in string and tubular piston means to condition said recess for the reception of said hanger seat therein.

16. In apparatus for suspending pipe in a well bore from a head having a recess therein: a split, inherently expandable hanger seat adapted to expand into the recess to provide a seat for supporting a string of pipe in the well bore; a running tool comprising body means connectible to a tubular running-in string for lowering toward the head; means releasably connecting said hanger seat in retracted condition to said body means; and means engageable with said hanger seat and shiftable relative to said body means for releasing said hanger seat from said body means to enable said hanger seat to expand inherently into the recess upon being lowered into transverse alignment therewith.

17. In apparatus as defined in claim 16; wherein said means for releasing said hanger seat comprises hydraulically actuatable means responsive to the pressure of fiuid in the tubular running-in string for shifting said hanger downwardly of said body means to released condition.

18. In apparatus as defined in claim 16; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; said means for releasing said hanger seat ejecting said hanger seat from encompassing relation by said skirt to permit said hanger seat to expand.

19. In apparatus as defined in claim 16; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; said means for releasing said hanger seat comprising hydraulically actuatable means responsive to the pressure of fluid in the tubular running-in string for ejecting said hanger seat from encompassing relation by said skirt to permit said hanger seat to expand.

20. In apparatus as defined in claim 16; cylinder means in said body means; said releasing means comprising tubular piston means in said cylinder means; and means adapted to be lowered through the tubular running-in string into engagement with said piston means to restrict the flow of fluid therethrough and allow fluid pressure to be built up in the tubular running-in string and cylinder means to shift said piston means downwardly in said cylinder means and shift said hanger seat downwardly of said body means to released condition.

21. In apparatus as defined in claim 16; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; cylinder means in said body means; said releasable means comprising tubular piston means in said cylinder means; and means adapted to be lowered through the tubular running-in string into engagement with said piston means to restrict the flow of fluid therethrough and allow fluid pressure to be built up in the tubular running-in string and cyilnder means to shift said piston means downwardly in said cylinder means and eject said hanger seat downwardly from encompassing relation by said skirt to permit said hanger seat to expand.

22. In apparatus as defined in claim 16; wherein said means releasably connecting said hanger seat to said body means comprises a skirt on said body means encompassing said hanger seat; cylinder means in said body means; said releasable means comprising tubular piston means in said cylinder means; means adapted to be lowered through the tubular running-in string into engagement with said piston means to restrict the flow of fluid therethrough and allow fluid pressure to be biult up in the tubular runningin string and cylinder means to shift said piston means downwardly in said cylinder means and eject said hanger seat downwardly from encompassing relation by said skirt to permit said hanger seat to expand; and a cleaning tool connectible to and depending from said tubular piston means and adapted to discharge fluid pumped down the running-in string and tubular piston means to condition the recess of the head for the reception of said hanger seat therein.

References Cited UNITED STATES PATENTS 2,016,454 10/1935 Penick et al 285-141 X 2,157,496 5/1939 Penick et a1. 285141 2,159,401 5/1939 Rector 16688 2,178,549 11/1939 Block 285-441 3,297,344 1/1967 Hanes 285-141 3,330,341 7/1967 Jackson et al. 166-.6

DAVID H. BROWN, Primary Examiner. 

1. IN APPARATUS FOR SUSPENDING PIPE IN A WELL BORE: A HEAD HAVING A CIRCUMFERENTIAL RECESS THEREIN; AN INHERENTLY EXPANDABLE HANGER SEAT ADAPTED TO EXPAND INTO SAID RECESS TO PROVIDE A SEAT FOR SUPPORTING A STRING OF PIPE IN THE WELL BORE; A RUNNING TOOL CONNECTIBLE TO A TUBULAR RUNNING-IN STRING FOR LOWERING TOWARD SAID HEAD; MEANS RELEASABLY CONNECTING SAID HANGER SEAT IN RETRACTED CONDITION TO SAID RUNNING TOOL; AND MEANS FOR RELEASING SAID HANGER SEAT FROM SAID RUNNING TOOL TO ENABLE SAID HANGER SEAT TO EXPAND INHERENTLY INTO SAID RECESS UPON BEING LOWERED INTO TRANSVERSE ALIGNMENT THEREWITH. 